When things are getting so rad that the levels of rad are surpassing the levels of gnar. Resulting in Radaculous (typically a term used amongst skaters)
Dude i can't believe you just ollied that gap, that was radaculous
Retarculous was originally coined by To Catch a Predator decoy, Emily Bicks. It is a conjunction of 'Retarded' and 'Ridiculous.' It is used to describe something that is extremely dumb, stupid, etc.
"Trying to use a trash bag as a parachute is absolutely retarculous."